1. Field of the Art
This disclosure is generally related to optics measuring and testing systems, and more specifically to a portable device for the flight-line boresighting of laser and imaging tracker systems. This disclosure is also generally related to laser safety systems, and more specifically to a novel shroud for the safe containment of a high power laser that is adjacent a sensitive imaging system.
2. Background
Guided missiles and bombs have been used for decades against aircraft, tanks, buildings, and bridges. The guidance sections for guided missiles and bombs often have seeker elements, mounted facing forward, which communicate inputs to fins or thrust vectoring mechanisms in order to steer. A seeker element “locks on” a target so that it follows the target if it moves in its field of view. Depending on the geometries, range, and carrier vehicles used, the guidance systems can lock on to a target before missile launch or bomb release, during the midcourse phase, or during the terminal engagement just before impact or fusing. Locking on to a target can be critical for aiming precision; therefore, it is no surprise that defenses to such weapons have employed countermeasures to dazzle, draw off, or otherwise confuse the seekers.
As technology has progressed over the years, seeker elements have been known to use radar, infrared, laser, optical tracking, or other methods to determine the location of and lock on their targets. Active countermeasures to such seekers employ waveform generators, chaff, flares, and other electronic countermeasures. Besides unidirectional countermeasures, directional countermeasures such as flash lamps, lasers, and other directed energy means have been developed. Each of these directed energy countermeasures is intended to be pointed at an incoming missile or bomb in order to confuse its seekers. Because closing velocities are often very fast, detection of an inbound target and pointing of such directed devices should be automated. Because high power directed energy beams are relatively narrow, their pointing should be highly accurate.
Infrared countermeasures (IRCM) systems are devices designed to protect aircraft from infrared homing missiles, sometimes called heatseeking missiles. They do so by confusing the missile guidance systems with a saturating beam of infrared light, typically from an infrared laser. A typical IRCM system consists of a primary imaging system (tracker) along with various laser systems that perform jamming, range finding and target designation. The performance of these subsystems should be periodically maintained during the operation of the IRCM system in order to insure that the IRCM system will work as intended at the critical time. For example, a laser in an IRCM system should be aligned to the center of the field-of-view of the primary imaging systems (tracker) such as a forward looking infrared (FLIR) camera, visible television (TV), or direct-view optics.
Few devices have been developed to simultaneously measure laser and imaging performance of ICRM systems, including measuring laser boresight, average power, pulse width, imager tracking target acquisition and lock, and field-of-view centroid to laser boresight. And the few devices that have been developed were apparently designed and intended for use at room temperature in a laboratory measurement station, at a factory test station, or in a similarly environmentally controlled depot test facility. This makes sense because testing in controlled temperatures and out of the weather can ensure the tightest alignment to standards and ensure safety of operators. The precision of these countermeasures can mean the difference between life and death.
Yet, a need exists for more accurate boresighting test equipment for ICRM and other countermeasure systems.